Means for securing an insert to a base piece

ABSTRACT

Means for removably securing an insert element to a larger base piece. The invention as disclosed solves the problem of securing an insert element such as a punch to a larger base piece such as a punch ring. The invention is particularly applicable to a rotary punch of the type having a rotating punch ring with punch elements removably secured around the periphery of said ring. In lieu of the usual set screw method of securing the punches to the punch ring quick releasable means is provided for fixedly but removably securing the shank of a punch or the like within a bore in the punch ring. The cross sectional contour of the shank or the bore is formed so that the shank engages the bore at two points in cross section. The shank is forced against said two points by means of a spring pressed ball so that the insert is urged simultaneously against the bottom of the bore and against the two points. The &#39;&#39;&#39;&#39;three point support&#39;&#39;&#39;&#39; thus achieved insures not only optimum stability of the insert with respect to the punch ring but also permits extremely accurate positioning of the punch relative to the punch ring.

United States Patent Petri [54] MEANS FOR SECURING AN INSERT TO A BASEPIECE [72] Inventor: Nello J. Petri, San Francisco, Calif.

[73] Assignee: Petri-Johnson, Inc., San Jose, Calif.

[22] Filed: March 10, 1971 [21] Appl. No.: 122,947

Primary Examiner-Andrew V. Kundrat Attorney-Gordon Wood 51 3,707,303[451 Dec. 26, 1972 57 I ABSTRACT Means for removably securing an insertelement to a larger base piece. The invention as disclosed solves theproblem of securing an insert element such as a punch to a larger basepiece such as a punch ring. The invention is particularly applicable toa rotary punch of the type having a rotating punch ring with punchelements removably secured around the periphery of said ring. In lieu ofthe usual set screw method of securing the punches to the punch ringquick releasable means is provided for fixedly but removably securingthe shank of a punch or the like within a bore in the punch ring. Thecross sectional contour of the shank or the bore is formed so that theshank engages the bore at two points in cross section. The shank isforced against said two points by means of a spring pressed ball so thatthe insert is urged simultaneously against the bottom of the bore andagainst the two points. The.three point support thus achieved insuresnot only optimum jstability of the insert with respect to the punch ringbut also permits extremely accurate positioning of the punch relative tothe punch ring.

3 Claims, 5 Drawing Figures PATENTEDUEEZS 1912 I 3,707,303

MEANS FOR SECURING AN INSERT TO A BASE PIECE This invention relates tomeans for accurately and firmly positioning a replaceable element withrespect to a larger member or base piece. The invention will bedescribed with respect to replaceable punch elements which areinsertedin the periphery of a rotatable punch ring for the purpose ofpunching holes in a paper strip or the like. However it will be apparentthat the invention herein'disclosed is applicable to many othersituations wherein it is desired to fixedly secure an element withrespect to a base piece so that such element may be removed and asimilar element replaced with a minimum loss of time.

I-Ieretofore paper punches of the type which include a ring rotatablysupported relative to a moving web of paper have been provided withreplaceable punches which are fixedly secured in radially outwardlyopening bores in the ring periphery. In order to fixedly secure saidpunches relative to the ring the procedure in the past has been toemploy a set screw threadedly secured within the ring and which screwmay be tightened against the shank of the punch. Since such punches mustbe replaced quite frequently it has been a time consuming operation torelease each one of the screws securing the punch elements and thentighten such screws after the new punch elements have been replaced. Thereason for employing such screw means for holding the punch elements isthat a high degree of accuracy is desired in punching apparatus and-theset screws provide means for not only holding the punch element in afixed position with reference to the punch ring bore but, since thepunch element is urged against one side of the bore a high degree ofaccuracy is ensured.

The main object of the present invention is the provision of means forfixedly securing punch elements within the periphery of a rotatablepunch ring without the use of set screws and similar devicesrequiringmanual loosening and tightening.

Another object of the invention is the provision of a relatively simpleholding device which not only secures the removableelement in placerelative to the base piece but also insures a high degree of accuracy inlocating the element relative to the bore within which it is receivedthus adding to the life of the punch.

Other objects and advantages will be apparent from the followingspecification and from the drawings:

FIG. l'is a fragmentary side view of a punch ring showing a plurality ofpunch elements in the periphery thereof.

FIG. 2 is a greatly enlarged cross sectional view of the punch ringshowing the insert in place and the holding means therefor.

FIG. 3 is a transverse cross .sectional view through the bore showingthe shank or the punch element received therein. The clearance betweenthe shank of the punch element and the bore in which it is received isgreatly exaggerated for clarity.

FIG. 4 is a view similar to FIG. 3 showing a modified form of theinvention.

FIG. 5 is a view similar to FIG. 3 showing another modified form of theinvention.

In detail, and first with reference to FIG. 1, the invention will bedisclosed with reference to a punching apparatus for punching holes in aweb of paper or the like. Such an apparatus includes a punch ringgenerally designated 1 carried by a shaft 2 which is rotatably supportedin suitable bearings (not shown). Upon rotation of the ring 1 over amoving web of paper the punches 3 on the periphery thereof cooperatewith dies on a die ring (not shown) to punch holes in the paper atpredetermined spaced points along the length of the latter. After aperiod of use the punches 3 become worn and must be replaced. Althoughsuch replaceable punches are relatively inexpensive the operation ofremoving the old punches and replacing them with new ones is a timeconsuming one since it is required to release and tighten set screws forholding such elements in place. The present invention is not concernedwith the punching operation itself but is concerned merely with the stepof removing the old punch elements and replacing them with new ones.

' As best seen in FIG. 2 the periphery of ring 1 is provided with aplurality of radially extending outwardly opening bores 5 each of whichis provided with a bottom 6. The punch generally designated 3 isprovided with an elongated shank portion 7 which may be'a fe'wthousandths of an inch less in diameter than the diameter of bore 5. Onone side of the bore 5 a transversely extending opening 9 is drilled toreceive a ball 10 and a strong compression spring 11. All of the springsmay be secured in place by a single annular spring retainer 12 fixed toring 1 by bolts (not shown). The spring 11 urges the ball 10 toward theadjacent side of the shank 7 and the inner end of hole 9 may be madefrustoconical or spherical as indicated at 14 to retain the ball withinthe hole 9 when the shank 7 is removed.

The ball 10 cooperates with a V-shaped groove 15 extending around theperiphery of shank 7 and having a pair of straight intersecting sidesl6, 17. As seen in FIG. 2 the length of shank 7 and the location of hole9 is predetermined so that the ball 10 engages the camming surface 17thus urging the inner end of shank 7 against the bottom 6 of the bore.The force of the spring 11 also urges the shank 7 against the side ofthe bore 5 that is opposite the ball 10. As best seen in FIG. 3 saidopposite side of the bore 5 is enlarged, preferably by milling, asindicated at 19. The depth of such enlargement 19 need not be very greatbut merely sufficient to cause the shank 7 to engage the inner side ofthe bore 5 along lines A and B (FIG. 3) extending longitudinally of thebore. By this structure it will be apparent that the shank 7 issubjected to a three point support in the sense that the ball 10 and thelines of engagement A, B are the only external means in engagement withthe punch shank 7 (neglecting the effect of the bottom 6 of the bore onthe inner end of the shank). It will be understood that the clearancesbetween the shank 7 and the bore 5 and the enlargement 19 areexaggerated in FIG. 3 for clarity. Actually in practice only a fewthousandths of an inch clearance is required between the shanks 7 andthe bore 5 in order to simplify the insertion and removal of the shank 7relative to the bore 5.

It has been found that the desired stability of the shank 7 relative tothe drum 1 cannot be achieved merely by urging the shank against theopposite cylindrical side of the bore 5. In other words if the lines ofengagement indicated at A and B are not clearly defined as by providingthe enlargement 19 the shank 7 tends to rock within the bore 5 thusmaking it impossible to keep the punch located with the desired degreeof accuracy.

The inner end of the shank 7 may be tapered as indicated at 21 tofacilitate the insertion of the shank within the bore.

The three point support noted above is of course actually brought aboutby the engagement of the shank 7 along two lines and the point at whichthe ball l0 engages the camming surface 17. Thus the term three pointsupport" as used herein is not exactly accurate but describes theimportant principle that by engaging the shank -7 at three differentlocations optimum stability is achieved. The efficacy of the structureis further enhanced by the presence of groove which divides each of thelines of engagements A, B into two spaced parts so that there are, ineffect, four lines of engagement on one side and point engagement on theopposite side.

Another form of the invention which also provides the so called threepoint support is shown in FlG.'4 wherein the ring 1' is provided with aside 30 spaced from the center line of the bore 5' a distance less thanthe radius ofthe latter so that the bore breaks out through said side30. By this structure the shank 7 engages the inner side of the bore atpoints A and B thus achieving a comparable stable support for the shank7.

An analogous structure is shown in FIG. 5 wherein the ring 1" isprovided with a bore 5 of circular cross section and the shank 7' isformed to provide a flat 32 along the side opposite the side engaged bythe ball 10. By this structure it will be apparent that similarsupporting lines A", B" are provided so as to effect a situationanalogous to that shown in FIG. 3.

The stability of the punch 3 relative to the ring 1 is further enhancedby the fact that the ball 10 urges the shank 7 against the bottom of thebore. Since the punching forces acting on the shank 7 tend to tilt it ina plane normal to the plane of the paper (FIG. 2) the cooperation of theinner end of the shank '7 with the bottom 6 also assists in resistingsuch tilting.

The very specific description of the invention herein disclosed shouldnot be taken as restrictive as it will be apparent that variousmodifications in design may be resorted to by those skilled in the artwithout departing from the scope of the following claims.

I claim:

1. In the combination that includes a base piece and an element securedthereto:

said base piece being formed with a bore opening outwardly of one facethereof,

said element including a shank adapted to be received in said borethrough the open end thereof, spring urged force means on one side ofsaid bore urging said shank transversely of said bore toward theopposite side thereof, I

said shank and bore being formed in cross section to provide two spacedpoints of engagement between said shank and said bore at said oppositeside,

the cross sectional contour of said shank being smaller than the crosssectional contour of said bore to provide clearance therebetween wherebythe periphery of said shank is engaged only by said force means and saidbore at said two points to provide stability of said element relative tosaid base piece,

said bore being provided with a bottom rigid with said base piece andsaid shank being provided with a camming surface acted upon by saidspring urged force means to urge said shank against said bottom at thesame time it is urged toward said opposite side,

said bore and shank being circular in cross section and said bore beingenlarged at the side opposite said force means to provide a pair ofjunctures at said points extending axially of said bore.

2. in the combination that includes a base piece and an element securedthereto: 7

said base piece being formed with a bore opening outwardly of one facethereof,

said element including a shank adapted to be received in said borethrough the open end thereof,

spring urged force means on one side of said bore urging said shanktransversely of said bore toward the opposite side thereof,

said shank and bore being formed in cross section to provide two spacedpoints of engagement between said shank and said bore at said oppositeside,

the cross sectional. contour of said shank being smaller than the crosssectional contour of said bore to provide clearance therebetween wherebythe periphery of said shank is engaged only by said force means and saidbore at said two points to provide stability of said element relative tosaid base piece,

said bore being provided with a bottom rigid with said base piece andsaid shank being provided with a camming surface acted upon by saidspring urged force means to urge said shank against said bottom at thesame time it is urged toward said opposite side,

the radius of said bore being less than the distance from the center ofthe bore to another face of said base piece whereby the bore intersectssaid other face to provide said points of engagement.

3. in the combination that includes a base piece and an element securedthereto:

said base piece being formed with a bore opening outwardly of one facethereof,

said element including shank adapted to be received in said bore throughthe open end thereof,

spring urged force means having a substantially spherical cammingsurface on one side of said bore urging said shank transversely of saidbore toward the opposite side thereof,

said shank and bore being formed in cross section to provide two spacedpoints of engagement between said shank and said bore at said oppositeside,

the cross sectional contour of said shank being smaller than the crosssectional contour of said bore to provide clearance therebetween wherebythe periphery of said shank is engaged only by said force means and saidbore at said two points to provide stability of said element relative tosaid base piece,

said bore being provided with a bottom rigid with said base piece andsaid shank being provided with an angled camming surface acted upon bysaid spring urged force means to urge said shank against said bottom atthe same time it is urged against said opposite side,

said camming surface being formed at such an angle so as to provide acomponent of the force of said force means urging said shank againstsaid opposite side which is greater than the component urging said shankagainst said bottom.

1. In the combination that includes a base piece and an element securedthereto: said base piece being formed with a bore opening outwardly ofone face thereof, said element including a shank adapted to be receivedin said bore through the open end thereof, spring urged force means onone side of said bore urging said shank transversely of said bore towardthe opposite side thereof, said shank and bore being formed in crosssection to provide two spaced points of engagement between said shankand said bore at said opposite side, the cross sectional contour of saidshank being smaller than the cross sectional contour of said bore toprovide clearance therebetween whereby the periphery of said shank isengaged only by said force means and said bore at said two points toprovide stability of said element relative to said base piece, said borebeing provided with a bottom rigid with said base piece and said shankbeing provided with a camming surface acted upon by said spring urgedforce means to urge said shank against said bottom at the same time itis urged toward said oppoSite side, said bore and shank being circularin cross section and said bore being enlarged at the side opposite saidforce means to provide a pair of junctures at said points extendingaxially of said bore.
 2. In the combination that includes a base pieceand an element secured thereto: said base piece being formed with a boreopening outwardly of one face thereof, said element including a shankadapted to be received in said bore through the open end thereof, springurged force means on one side of said bore urging said shanktransversely of said bore toward the opposite side thereof, said shankand bore being formed in cross section to provide two spaced points ofengagement between said shank and said bore at said opposite side, thecross sectional contour of said shank being smaller than the crosssectional contour of said bore to provide clearance therebetween wherebythe periphery of said shank is engaged only by said force means and saidbore at said two points to provide stability of said element relative tosaid base piece, said bore being provided with a bottom rigid with saidbase piece and said shank being provided with a camming surface actedupon by said spring urged force means to urge said shank against saidbottom at the same time it is urged toward said opposite side, theradius of said bore being less than the distance from the center of thebore to another face of said base piece whereby the bore intersects saidother face to provide said points of engagement.
 3. In the combinationthat includes a base piece and an element secured thereto: said basepiece being formed with a bore opening outwardly of one face thereof,said element including shank adapted to be received in said bore throughthe open end thereof, spring urged force means having a substantiallyspherical camming surface on one side of said bore urging said shanktransversely of said bore toward the opposite side thereof, said shankand bore being formed in cross section to provide two spaced points ofengagement between said shank and said bore at said opposite side, thecross sectional contour of said shank being smaller than the crosssectional contour of said bore to provide clearance therebetween wherebythe periphery of said shank is engaged only by said force means and saidbore at said two points to provide stability of said element relative tosaid base piece, said bore being provided with a bottom rigid with saidbase piece and said shank being provided with an angled camming surfaceacted upon by said spring urged force means to urge said shank againstsaid bottom at the same time it is urged against said opposite side,said camming surface being formed at such an angle so as to provide acomponent of the force of said force means urging said shank againstsaid opposite side which is greater than the component urging said shankagainst said bottom.